Field
Exemplary embodiments relate to a thin film transistor array panel and a manufacturing method thereof.
Discussion
Thin film transistors (TFTs) are used in various electronic devices, such as flat panel displays. For example, TFTs are used as switching devices or driving devices in flat panel displays, such as liquid crystal display (LCDs), organic light emitting diode (OLED) displays, plasma displays (PDs), electrophoretic displays (EPDs), electrowetting displays (EWDs), and the like.
A TFT typically includes a gate electrode connected to a gate line transmitting a scan signal, a source electrode connected to a data line transmitting a signal to be applied to a pixel electrode, a drain electrode facing the source electrode, and a semiconductor connected to the source electrode and the drain electrode. Among these components, the semiconductor, which is a significant factor in determining the characteristics of a TFT, may be formed of, for instance, amorphous silicon, poly-crystalline silicon, etc., an oxide-based material, etc.
When used in association with flat panel displays, a TFT array panel may include a plurality of TFTs, which may include various different types of semiconductor materials, as well as include two or more semiconductor layers formed, for instance, in different patterning steps. For example, a TFT array panel may include a TFT including a semiconductor layer including poly-crystalline silicon and a TFT including a semiconductor layer including amorphous silicon. When the semiconductor layer is formed by using, for example, one or more photolithographic processes, the different semiconductor layers may be formed using different optical masks (or reticles) in different patterning steps.
Accordingly, a first semiconductor may be formed between the different semiconductor layers included in the TFT array panel and, thereby, referred to as a first semiconductor, and a semiconductor formed later may be referred to as a second semiconductor. The first semiconductor may be patterned before the second semiconductor through, for example, an etching process. An etching passivation layer may be disposed on the patterned first semiconductor to protect the first semiconductor. An edge portion of the first semiconductor may be exposed during another etching process to form the second semiconductor. In this manner, uneven protrusions may be created at the edge portion of the first semiconductor. As such, when an electrode is formed on the uneven protrusions at the edge of the first semiconductor, the electrode may be short-circuited.
Therefore, there is a need for an approach that provides efficient, cost effective techniques to manufacture TFT array panels to prevent (or otherwise reduce) the potential for short-circuits due to, for example, uneven protrusions.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention, and therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.